SQL PROGRAMMING STYLE- P35 docx

... the actual problem. Exceptions: If your SQL product supports the SIMILAR TO predicate (a version of grep() based on the POSIX standard in Standard SQL) , then you might consider having a longer ... Table Declaration Rationale: These constraints are not yet well supported in SQL products, but they are legal SQL- 92 syntax. Their predicates involve the entire table as a whole...

Ngày tải lên: 06/07/2014, 23:20

... predicates or CASE expressions. As an example of a horrible misuse of SQL, Chris White posted a procedure that built dynamic SQL that would then build a report. Aside from the obvious violations ... what you actually want. The other set operations in SQL- 92, EXCEPT [ALL], and INTERSECT [ALL] are not widely available yet. 6.11 Testing SQL When you are first writing a schema, you wi...

Ngày tải lên: 06/07/2014, 23:20

... score means and why it is incremented. In Standard SQL, a comment begins with two dashes ( ) and ends with a new line, because the first SQL engines were on IBM mainframes and used punchcards. ... brackets. They are a better choice. SQL programmers do not like to put comments in their code, not even redundant or useless ones. My guess is that because SQL does a lot of work in one...

Ngày tải lên: 06/07/2014, 23:20

... really fast on the current release of my SQL software? A1: Sure, if I want to lose all of the advantages of an abstract data model, SQL set-oriented programming, carry extra data, and destroy ... faster and easy to program. A2: This is an implementation problem that the SQL engine can handle. For example, Teradata is a SQL designed for very large database (VLDB) applications that...

Ngày tải lên: 06/07/2014, 23:20

... and so forth. SQL Server and Sybase used different fixes for this problem in later versions of their products. Sybase did a hidden “SELECT DISTINCT” in the implied query, and SQL Server gets ... Standard SQL is consistent and clear about aliases, views, and derived tables, as well as a highly orthogonal language. If the UPDATE clause could take an alias, according to the Standard SQ...

Ngày tải lên: 06/07/2014, 23:20

... SECTION | SELECT | SESSION | SESSION_USER | SET | SIZE | SMALLINT | SOME | SPACE | SQL | SQLCODE | SQLERROR | SQLSTATE | SUBSTRING | SUM | SYSTEM_USER | TABLE | TEMPORARY | THEN | TIME | TIMESTAMP ... have to wrap exceptionally long lines. This is not as big a problem in a concise language like SQL as it was in a verbose language like COBOL. 2.1 Typography and Code 29 | MATCH...

Ngày tải lên: 06/07/2014, 23:20

... Additionally, capitalization represents proper nouns—like the names of sets being modeled by tables in SQL in English, German, and other natural languages. This is the way that readers expect to see ... Not only are words seen as wholes, but they are also anticipated within each statement in the programming language. That is, if I see an “IF” token in Pascal or another member of the A...

Ngày tải lên: 06/07/2014, 23:20

... ignorance and object-oriented (OO) programming. In particular, OO programmers put “_id” on every primary key in every table and have problems understanding that SQL is a strongly typed language ... from table to table. As an example, consider this slightly cleaned- up piece of actual code from a SQL newsgroup: SELECT Incident.Type, IPC.DefendantType, Recommendation.Notes, Offence.S...

Ngày tải lên: 06/07/2014, 23:20

... of the most important SQL schema objects according to ISO and several popular SQL products. 6 CHAPTER 1: NAMES AND DATA ELEMENTS Will this work? According to the SQL standard, it should ... of Names Rationale: The SQL- 92 standards have a maximum identifier length of 18 characters. This length came from the older COBOL standards. These days, SQL implementations allow lo...

Ngày tải lên: 06/07/2014, 23:20

... programmers. My goals in this book are to improve SQL programming style and proficiency. To be more exact: 1. To help an individual programmer write Standard SQL without an accent or a dialect . ... other SQLs, cannot be easily understood by an end user, and cannot be expanded. In the second case, what some newbies, who are still thinking in terms of second- and third-generati...

Ngày tải lên: 10/04/2014, 09:40